The Greek extremist group Conspiracy of Fire Nuclei on Tuesday claimed responsibility for a series of parcel bombs that were sent to foreign leaders and embassies earlier this month, police said.

Two presumed members of the group — who were arrested in Athens and placed under provisional detention in the wake of the parcel bomb scares — claimed responsibility in a letter sent to the Indymedia website.

The letter claimed responsibility for “the dispatch of parcel bombs to French President Nicolas Sarkozy, the headquarters of the World Court in the Hague and the embassies of Belgium and Mexico in Athens.”

More than a dozen packages containing explosives were sent from Greece to European leaders and foreign embassies on Nov. 4 and 5.

A total of 13 presumed members of the extremist group are being sought by Greek authorities who view it as a “terrorist” organization.